To meet the demand for wireless data traffic having increased since deployment of 4th generation (4G) communication systems, efforts have been made to develop an improved 5th generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
Mm-wave technology is expected to form a part of fifth generation (5G) radio access networks. It can improve capacity compared to lower frequency deployments in macro, micro, metro or localised hotspots but can also provide a consistent user experience in a standalone configuration i.e. even without support from lower frequency carriers.
However, there are certain problems experienced when using mm-wave radio signals. In particular, mm-wave radio propagation behaviour is similar to optical signals, having low diffractions and increasingly relies upon line-of sight (LoS) or strong reflections from surrounding environment due to narrow beamforming, rather than diffuse components. As a result, mm-wave signals are more outage-prone compared to low-frequency carriers, and signal blockage can be induced by trees, street furniture, transport traffic and even human bodies. Signal blockage (in either the control or data channel) may lead to an abrupt reduction in link quality or to radio link failures (RLFs) with drastic impacts on transport layer control protocols (e.g. TCP). This, in turn, can lead to a degraded quality of experience (QoE) for end-user equipment's (UEs).